JP2003003014A - High damping rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high damping rubber composition that maintains high damping properties with no deterioration of temperature dependency and mechanical properties. SOLUTION: The high damping rubber composition is obtained by impregnating rubber containing natural rubber and/or isoprene rubber with a rosin- modified phenol and/or a rosin ester. The high damping rubber composition is further obtainable by impregnating rubber containing natural rubber and/or isoprene rubber with carbon black, silica and a rosin-modified phenol and/or a rosin ester. Preferably rubber containing natural rubber and/or isoprene rubber is impregnated with 20-80 pts.wt. of carbon black, 30-80 pts.wt. of silica and 10-60 pts.wt. of a rosin-modified phenol and/or a rosin ester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-damping rubber composition, and more specifically, to vibration and vibration control of automobiles, various machines and the like, seismic isolation and other vibration control,
The present invention relates to a high damping rubber composition for absorbing various vibrational energy such as vibration damping.

[0002]

2. Description of the Related Art Devices and machines that absorb various types of vibrational energy such as seismic isolation and other vibration control and vibration control have been attracting attention. The seismic isolation rubber device 1 shown in FIG. 1 is configured by laminating a rubber layer 2 and a hard plate 3 such as a steel plate. An upper mounting plate 4 is fixed to the upper part of the stack, and a lower mounting plate 5 is fixed to the lower part of the stack. Here, the high damping rubber composition forming the rubber layer 2 is
Damping of vibration energy is obtained by using natural rubber, which has excellent mechanical properties, as a main component.

For example, Japanese Patent Laid-Open No. 7-126437,
Japanese Patent Publication No. 2949671 discloses a high damping rubber composition containing natural rubber and synthetic isoprene rubber as rubber components.

However, the high damping rubber composition is required to have not only damping properties but also cold resistance, puncture resistance, long-term stability of performance, workability and the like.
For example, there is a problem that if the attenuation rate of the rubber composition is increased, the cold resistance decreases (the temperature dependence increases).

There are some which try to obtain a high damping property by blending a large amount of carbon black having a small particle diameter or a large amount of silica in natural rubber. For example, Japanese Patent Publication No. 2762407 discloses a high damping rubber composition containing rubber containing natural rubber as a main component, a thermoplastic hydrocarbon resin, and carbon black having predetermined characteristics. However, the high-damping rubber composition disclosed herein has a nitrogen adsorption specific surface area of 70 to 11 of carbon black.
At 0 m ² / g, the damping property is still insufficient, and the damping property is compensated by adding a large amount of the thermoplastic hydrocarbon resin, but in this case, the cold resistance decreases.

Further, the above-mentioned Japanese Patent Publication No. 294967.
No. 1 contains 5 natural rubber and / or isoprene rubber.
100 parts by weight of rubber containing 0 part by weight or more, 15 to 60 parts by weight of petroleum resin, 60 to 95 parts by weight of fine particle carbon black and silica, and a weight part ratio of fine particles of carbon black and silica of 95/5 to 75. A high damping rubber composition in the range of / 25 is disclosed, and it is stated that a low elastic modulus can be obtained without reducing the damping property by using silica by replacing a part of carbon black. However, in this rubber composition, the compounding amount of carbon black increases, and the temperature dependence is deteriorated.
Further, the nitrogen adsorption specific surface area of carbon black is 60 to 15
When it is 0 m ² / g, the damping property and the elongation at break are insufficient.

Further, Japanese Patent Publication No. 2902468 discloses that
A high damping rubber composition in which silica is blended with a rubber component containing natural rubber as a main component is disclosed. However, this rubber composition improves the damping property as compared with a large amount of silica without surface treatment. Therefore, there is a drawback that the workability is poor. Then, the dispersibility of silica is worse than that of silica which has been surface-treated. As a result, the reinforcing property can hardly be expected, and it becomes difficult to adjust to any rigidity, particularly to obtain a high rigidity type rubber composition.

JP-A-9-124843 and WO
Japanese Patent Publication No. 98/32794 discloses a high damping rubber composition in which a large amount of carbon black is mixed with a rubber component containing natural rubber as a main component. However, when a large amount of carbon black is mixed, high rigidity is achieved as described above. And high attenuation can be achieved, but the temperature dependence becomes worse.

Further, in Japanese Patent Application Laid-Open No. 4-212844, a relatively large amount of carbon black is blended, and an aromatic petroleum resin, coumarone indene resin, and rosin are blended with rubber to obtain high damping properties. We are trying to realize a composition for seismic isolation laminate, which is excellent in temperature dependence of elastic modulus and shear deformation elongation.

However, when a large amount of carbon black is blended, a high damping is obtained, but there is a drawback that the elongation of rubber is generally lowered. Generally, the addition of resin is
The temperature dependency of the rubber composition is deteriorated. Further, when a large amount of resin is blended, a high damping property can be obtained, but there is a drawback that workability is deteriorated due to adhesion.

For these reasons, conventionally, there has been a problem that the elongation of the rubber is large, and if it is attempted to improve the temperature dependence, a high damping cannot be obtained.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks, and an object of the present invention is to reduce the temperature dependence and mechanical characteristics without causing a small deformation. And during large deformation (for example, 200% deformation)
To provide a high damping rubber composition having a high damping property.

[0013]

The high damping rubber composition of the present invention contains a rosin-modified phenol and / or a rosin ester for a rubber containing a natural rubber and / or an isoprene rubber. The purpose is achieved.

In one embodiment, for the rubber containing natural rubber and / or isoprene rubber, carbon black, silica, and rosin-modified phenol and / or rosin ester are contained.

In one embodiment, the content of the rosin-modified phenol and / or rosin ester is 5 to 60 parts by weight based on 100 parts by weight of the rubber.

[0016] In one embodiment, the content of the carbon black is 2 with respect to 100 parts by weight of the rubber.
It is 0 to 80 parts by weight.

In one embodiment, the content of the silica is 30 to 80 parts by weight based on 100 parts by weight of the rubber.

In one embodiment, the carbon black has a nitrogen adsorption specific surface area of 130 to 300 m ² /
g, and the DBP oil absorption of the carbon black is 60 to 1
50 ml / 100 g.

In one embodiment, the nitrogen adsorption specific surface area of the silica is 150 to 500 m ² / g, and the DBP oil absorption of the silica is 160 to 350 ml / 100 g.

The operation of the present invention is as follows.

By blending a rosin-modified phenol and / or a rosin ester with a rubber whose main component is natural rubber having excellent mechanical properties, high damping and temperature dependence can be improved. Various rosin derivatives are commercially available. Among them, a high-damping rubber composition using a rosin-modified phenol and a rosin ester has high damping and temperature dependence without impairing other properties. I found that it could be improved.

Furthermore, in the present invention, by adding fine particles of carbon black, it is possible to obtain higher damping and greater elongation.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION (Rubber) The rubber base material (unvulcanized rubber) used in the high damping rubber composition of the present invention contains natural rubber and / or isoprene rubber as a main component.

Other rubbers that can be compounded in addition to natural rubber include butadiene rubber, butyl rubber, styrene / butadiene copolymer rubber, acrylonitrile / butadiene copolymer rubber, halogenated butyl rubber, chloroprene rubber, silicone rubber, silicone modified rubber, ethylene. Examples include unvulcanized rubber such as propylene copolymer rubber, thermoplastic elastomers having a sufficiently low elastic modulus at around room temperature, liquid rubber, and the like. (Carbon Black and Silica) The high damping rubber composition of the present invention contains silica having a specific surface area and a DBP oil absorption in a specific range, and carbon black.

As the silica used in the present invention, synthetic silica such as wet silica and dry silica can be used. What is called white carbon (fine silica) is preferably used as the silica, and specifically, any of fine powder of silicic acid anhydride, hydrous silicic acid, calcium silicate, aluminum silicate and the like may be used without any particular limitation.

The specific surface area of the silica used is 150-50.
0 m ² / g and the silica DBP oil absorption is 160
A rubber composition of up to 350 ml / 100 g has a high damping property and a large elongation.

The preferred specific surface area of silica is 180-40.
0 m ² / g, and a particularly preferred specific surface area of silica is 1
It is 80 to 350 m ² / g. The DBP oil absorption of silica is preferably 200 to 350 ml / 100 g.

When the specific surface area of silica is 500 m ² / g or more, the elongation at break of the high damping rubber decreases. Silica is
Those having a primary particle diameter of 1 to 30 nm are preferable.

Silica is 30 per 100 parts by weight of rubber.
It is preferable to contain ˜80 parts by weight. If the blending amount of silica is too small, the damping property is lowered, and if it is too large, the workability is lowered. The specific surface area of silica is the BET method (DIN661
It can be measured using nitrogen gas by the method shown in 31). Various surface treatment agents, modifiers and the like may be added to improve the reinforcing property and processability of silica. Specifically, silane coupling agents and ethylene glycols can be added in any amount as long as they do not impair the physical properties.

In the present invention, one or more kinds of carbon black may be used, but the characteristics of the carbon black mainly used are as follows.

The nitrogen adsorption specific surface area of carbon black is
130~300m is a ² / g, especially 200~300m ²
/ G is preferred. The DBP oil absorption of carbon black is 60 to 150 ml / 100 g, and particularly 60 to 150 ml / 100 g.
120 ml / 100 g is preferred.

By using carbon black having a nitrogen adsorption specific surface area within the above range, the damping property of the high damping rubber becomes high and the elongation at break becomes large. When the nitrogen adsorption specific surface area of the carbon black is less than 160 m ² / g, the damping property and elongation at the time of large deformation are reduced.

The smaller the DBP oil absorption of carbon black is, the more advantageous it is in the damping property and elongation at break of the rubber material, but if it is less than 60 ml / 100 g, the dispersibility in the rubber composition will be poor. If it exceeds 150 ml / 100 g, the rigidity becomes high, and the damping property and breaking elongation of the rubber material become insufficient.

By using the ultrafine carbon black as described above, the damping property at the time of large deformation can be enhanced with a small amount of compounding. Also, the breaking elongation can be increased.

Specifically, there are commercially available products such as BLACK PEARLS 880 (manufactured by Cabot Specialty Chemicals Inc.) and carbon black # 8500 (manufactured by Tokai Carbon Co., Ltd.).

The nitrogen specific surface area of carbon black is AST
It can be measured by the method shown in MD3037-89, that is, by determining the particle size by the amount of nitrogen gas adsorbed.

Carbon black is preferably contained in an amount of 20 to 80 parts by weight based on 100 parts by weight of rubber. The blending of carbon black is preferable for the rubber composition of the present invention to exhibit damping properties. If the blending amount of carbon black is too small, the damping property of the high-damping rubber is inferior, and if the blending amount of carbon black is excessive, the processability is lowered during the production of the rubber composition, which is not preferable in the production, and the high damping rubber The elongation at break also decreases. The above-mentioned physical properties of carbon black have a great influence on the damping property of the rubber material (high damping rubber). Further, in the present invention, by using the carbon black in the above range, a rubber composition having good physical properties can be obtained.
Part of carbon black outside the above range may be used to reduce the cost.

The rubber composition of the present invention contains the above-mentioned carbon black and silica in a total amount of 5 parts by weight per 100 parts by weight of the rubber.
The amount is preferably 0 to 160 parts by weight, more preferably 50 to 120 parts by weight. If it is less than 50 parts by weight, the damping property of the rubber composition is insufficient, and if it exceeds 160 parts by weight,
It is not preferable because the workability and the elongation at break of the obtained high damping rubber are reduced.

When carbon black is contained,
The weight ratio of carbon black to silica is preferably 30 to 70 parts by weight of silica to 20 to 50 parts by weight of carbon black. (Rosin derivative) Examples of rosin include gum rosin obtained from raw pine trees, wood rosin obtained from pine stumps, and tall oil rosin obtained by treating kraft pulp chips. Rosin exists as a complex containing azeethynic acid as a main component and pimaric acid or the like as an accessory component. Various treatments are performed on the rosin to obtain a rosin derivative.

As the rosin derivative, a rosin-modified phenol modified with a phenol resin, a rosin ester modified with a polyol, a hydrogenated rosin for hydrogenation, a disproportionated rosin with a disproportionation catalyst, and a disproportionation for further esterification thereof There are rosin ester, rosin-modified maleic acid resin treated with maleic acid, polymerized rosin that polymerizes, and polymerized rosin ester that further esterifies it.

Among these rosin derivatives, when a rosin-modified phenol is added to a rubber composition, the rubber has a large elongation, is excellent in temperature dependence, and is capable of obtaining a high damping property. In particular, when the rosin ester is added to the rubber composition, the rubber has a large elongation and high damping can be obtained.

Specific examples include rosin-modified phenol (Tamanor 901, Arakawa Chemical Industry Co., Ltd.), rosin ester (ester gum AAL, Arakawa Chemical Industry Co., Ltd.) and the like.

These are compounded in an amount of 5 to 60 parts by weight, preferably 10 to 30 parts by weight, based on the rubber composition. If the blending amount is less than 5 parts by weight, the effect on the high damping property is small, and if it exceeds 60 parts by weight, the workability is deteriorated. These may be used alone or as a mixture. (Additives, carbon black, fillers other than silica,
Lubricants) Resins other than rosin esters and rosin-modified phenols can be appropriately added to the rubber composition of the present invention.

The resin includes phenol resin, rosin-modified resin, DCDP resin, C5 petroleum resin, C9 petroleum resin, alicyclic petroleum resin, and C5 and C9 copolymers. These may be used alone or in combination.

The resin is 100 parts by weight of the total rubber,
It may be added in an amount of 1 to 50 parts by weight, preferably 1 to 30 parts by weight.

In producing the high damping rubber composition (vulcanized rubber composition) of the present invention, in addition to the above components, the vulcanizing agent such as sulfur, vulcanizing zinc white, stearic acid and the like are added to the unvulcanized rubber. Auxiliary agents, vulcanization accelerators, vulcanization delay agents, antioxidants, softeners (process oil etc.), plasticizers, tackifiers, resins, inorganic fillers, lubricants, and other additives as required. It can be added to unvulcanized rubber.

The high-damping rubber composition (unvulcanized rubber composition) containing these compounding agents is appropriately molded, and by using a method and an apparatus known per se, 110 ° C. to 17 ° C.
It is vulcanized at 0 ° C. to obtain a high damping rubber (vulcanized rubber).

[0048]

EXAMPLES The vulcanized rubbers obtained in the following examples and comparative examples were evaluated for the physical properties shown below. The materials used are shown below. A. Evaluation method of physical properties (1) G (MPa) at 200% deformation Using the dynamic servo of Sagimiya Seisakusho, using the test piece 4 shown in Fig. 2, "Handbook of seismic isolation laminated rubber for designers" (corporate association) Measured and evaluated by the method described in the Japan Rubber Association Seismic Isolation Laminated Rubber Committee). The test conditions are a frequency of 0.3 Hz and a deformation amount of 2 against the rubber thickness.
The rigidity at 20 ° C. when the shear test was performed at 00% was obtained. (2) Attenuation rate (%) at 200% deformation By the same test method and test conditions as G at 200% deformation,
The decay rate was calculated. (3) Temperature Dependence Ratio (-10 ° C / 20 ° C) By the same test method as G at 200% deformation, a frequency of 0.
The ratio of the elastic moduli at −10 ° C. and 20 ° C. when sheared was 3 Hz, the deformation amount was 100% with respect to the rubber thickness, and the temperature dependence ratio of rigidity (−10 ° C./20° C.) was calculated. (4) Breaking elongation (EB) (%) Measured in accordance with JIS K6251. The larger the value, the larger the breaking elongation.

In the figure, reference numeral 6 indicates a test piece, and 7 indicates a high damping rubber made of the high damping rubber composition of the test piece 6. (Examples 1 to 7 and Comparative Examples 1 to 13) Table 1 and Table 2
As shown in Table 1, natural rubber, butyl rubber, carbon black, silica (white carbon), and various rosin derivatives were added in the amounts shown in Tables 1 and 2, and 5 parts by weight of zinc white, 2 parts by weight of stearic acid, and 1% of sulfur were added. Parts by weight, antioxidant 6 parts by weight, oil 15 parts by weight, vulcanization accelerator (CBS)
2.5 parts by weight were compounded and kneaded to prepare an unvulcanized rubber composition.

This rubber composition was pressed at 150 ° C. for 30 minutes and vulcanized to obtain a vulcanized rubber.

The physical properties of the silica and carbon black used were as follows. Silica: Specific surface area: 195 m ² / g, DBP oil absorption: 1
90 ml / 100 g, wet silica carbon black: nitrogen adsorption specific surface area: 220 m ² /
g, DBP oil absorption: 105 ml / 100 g The rosin derivative used is as follows. Polymerized rosin ester: Pencel D-125 (manufactured by Arakawa Chemical Industry Co., Ltd.) Hydrogenated rosin: High Pale (manufactured by Arakawa Chemical Industry Co., Ltd.) Disproportionated rosin: Rosin R (manufactured by Arakawa Chemical Industry Co., Ltd.) Rosin modified malein Acid resin: Marquide No. 1 (manufactured by Arakawa Chemical Industry Co., Ltd.) Disproportionated rosin ester: Super ester A-125
(Arakawa Chemical Industry Co., Ltd.) Rosin ester: ester gum AAL (Arakawa Chemical Industry Co., Ltd.) Rosin-modified phenol: Tamanor 901 (Arakawa Chemical Industry Co., Ltd.) C9 petroleum resin: Nisseki Neopolymer 120 ( The product of Nippon Petrochemical Co., Ltd. The results of the above Examples and Comparative Examples are shown in Tables 1 and 2.

[0052]

[Table 1]

[0053]

[Table 2] From these results, the following can be seen.

A rosin derivative having a high heq at 200% deformation, a low temperature dependence and a large sheet elongation is preferable as the high damping rubber composition. Of the rosin derivatives, the best material is rosin-modified phenol and then rosin ester.

[0055]

EFFECTS OF THE INVENTION According to the present invention, since a rosin-modified phenol and / or a rosin ester is blended with a rubber mainly composed of natural rubber having excellent mechanical properties, both high damping and low temperature dependence are achieved. Can, car,
It can be suitably used as a high-damping rubber composition for absorbing various vibrational energy such as vibration damping and vibration damping for various machines and the like, seismic isolation for earthquakes, and other vibration damping and damping.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a seismic isolation bearing using high damping rubber.

FIG. 2 is an explanatory diagram of a test piece used in an example of the present invention.

[Explanation of symbols]

1 Seismic isolation rubber device 2 rubber layers 3 hard plate 4 Upper mounting plate 5 lower mounting plate, 6 test pieces 7 High damping rubber

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16F 15/08 F16F 15/08 D (72) Inventor Shin Maezawa 172 Ikezawa-cho, Yamatokoriyama City, Nara Nitta Stock Company Nara Factory (72) Inventor Shinichi Sato 172 Ikezawa-cho, Yamatokoriyama City, Nara Nitta Stock Company F Term in Nara Factory (reference) 3J048 AA01 BA01 BD04 4J002 AC011 AC061 AF022 CC032 DA036 DJ017 FD016 FD017 FD140 FD150 GM00

Claims (7)

[Claims] 1. A rubber containing natural rubber and / or isoprene rubber, and rosin-modified phenol and / or
Alternatively, a high damping rubber composition containing a rosin ester. 2. A rubber containing natural rubber and / or isoprene rubber, carbon black, silica,
And a high damping rubber composition containing rosin-modified phenol and / or rosin ester. 3. The high damping rubber composition according to claim 1, wherein the content of the rosin-modified phenol and / or rosin ester is 5 to 60 parts by weight with respect to 100 parts by weight of the rubber. 4. The high damping rubber composition according to claim 2, wherein the content of the carbon black is 20 to 80 parts by weight with respect to 100 parts by weight of the rubber. 5. The rubber 100 has a content of silica.
The high damping rubber composition according to any one of claims 2 to 4, which is 30 to 80 parts by weight based on parts by weight. 6. The high damping according to claim 2, wherein the carbon black has a nitrogen adsorption specific surface area of 130 to 300 m ² / g, and the carbon black has a DBP oil absorption of 60 to 150 ml / 100 g. Rubber composition. 7. The nitrogen adsorption specific surface area of the silica is 150.
~ 500 m ² / g, and the silica has a DBP oil absorption of 16
It is 0-350 ml / 100g, The high damping rubber composition in any one of Claims 2-6.